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https://issues.apache.org/jira/browse/OAK-3005?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14589661#comment-14589661
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Chetan Mehrotra commented on OAK-3005:
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[~shgu...@adobe.com] Given we already use Guava in Oak it might be better to
just make use of them and have a simple CachingDataStore impl. Have a look at
{{DataStoreBlobStore#getInputStream}} where we have some caching done for small
binaries on heap.
Extrapolating that design in following way would allow us to implement a simple
FS based caching layer
# Have a new cache where the cached value is File (or some instance which keeps
a reference to File)
# Provide support for Weight via a simple
[Weigher|http://docs.guava-libraries.googlecode.com/git-history/release/javadoc/com/google/common/cache/Weigher.html]
which is based on File size
# Register a
[RemovalListener|http://docs.guava-libraries.googlecode.com/git-history/release/javadoc/com/google/common/cache/RemovalListener.html]
which removes the file from file system upon eviction
# Provide a loader which spools the remote binary to local filesystem
This should be a small logic and would provide you all benefits of Guava cache
including cache stats. And this would transparently work for any DataStore.
May be we implement it at {{BlobStore}} level itself and then it would be
useful for other BlobStore also. Doing it at BlobStore level would require some
support from {{BlobStore}} to determine the blob length from blobId itself.
[1] https://code.google.com/p/guava-libraries/wiki/CachesExplained
> OSGI wrapper service for Jackrabbit CachingFDS
> ----------------------------------------------
>
> Key: OAK-3005
> URL: https://issues.apache.org/jira/browse/OAK-3005
> Project: Jackrabbit Oak
> Issue Type: Improvement
> Components: blob
> Affects Versions: 1.0.15
> Reporter: Shashank Gupta
> Assignee: Shashank Gupta
> Labels: features, performance
> Fix For: 1.0.16
>
> Attachments: OAK-2729.patch
>
>
> OSGI service wrapper for JCR-3869 which provides CachingDataStore
> capabilities for SAN & NAS storage
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